Generating method and generator for generating mist or fine-bubble by using surface acoustic wave

Abstract

In a generating method and a generator of mist or fine-bubble, with a simple and small configuration, application into a wide range kind of liquid is enabled, and generating stably the mist or the fine-bubbles or both is enabled. The generator is provided with a piezoelectric substrate which equips two or more comb-like electrodes on a surface and arranged so that the surface may intersect the mutual interface of the gas and the liquid and a part of piezoelectric substrate is put in a liquid, and a surface acoustic wave excited on the surface with the electrode is made to propagate along the surface so that may exist in the upper and lower sides of an interface. The surface acoustic wave generates mist in the gas side which is above the interface, and generates fine-bubbles in the liquid side which is below the interface. Since the mist and the fine-bubbles are generated with the surface acoustic wave, without being based on mechanical operation for generating a turning stream, the mist and the fine-bubbles can be stably generated in the simple and small configuration.

1 . A generating method for generating mist or fine-bubble, comprising the steps of:
 arranging in a liquid a part of a piezoelectric substrate having a surface, said surface intersecting a mutual interface of gas and the liquid and equipped thereon with an excitation means consisting of a plurality of electrodes to excite surface acoustic wave;   exciting a surface acoustic wave on the surface with the excitation means; and   propagating the excited surface acoustic wave along the surface so that the surface acoustic wave to exist in the upper and lower sides of the interface and the surface acoustic wave to generate mist in the gas side upon the wave being above the interface and to generate fine-bubbles in the liquid side upon the wave being below the interface.   
     
     
         2 . A generating method for generating mist or fine-bubble according to  claim 1 , further comprising:
 arranging the piezoelectric substrate so that the excitation means to be in the gas side;   preparing a cover sticking on a region in the surface including at least a region intersecting the interface; and   propagating the surface acoustic wave excited by the excitation means along the surface from the gas side to the liquid side to generate fine-bubbles inside the liquid away from the interface.   
     
     
         3 . A generating method for generating mist or fine-bubble according to  claim 2 , wherein the cover being prepared further in a region for covering the excitation means. 
     
     
         4 . A generating method for generating mist or fine-bubble according to  claim 1 , wherein providing a container wrapping a portion of the piezoelectric substrate in the gas side to confine the mist in a space formed with the container and the liquid. 
     
     
         5 . A generating method for generating mist or fine-bubble according to  claim 1 , wherein providing a plate in a position intersecting the interface, said plate approaching and facing the surface. 
     
     
         6 . A generating method for generating mist or fine-bubble according to  claim 1 , wherein changing a generation ratio of the mist or the fine-bubbles by changing an angle of intersection between the surface and the interface. 
     
     
         7 . A generating method for generating mist or fine-bubble according to  claim 1 , wherein the surface being covered by an insulator to cover at least the excitation means. 
     
     
         8 . A generating method for generating mist or fine-bubble according to  claim 1 , wherein a substrate-thickness of the piezoelectric substrate being made into the substrate-thickness so that the surface acoustic wave excited by the excitation means to propagate on a rear-surface countering the surface. 
     
     
         9 . A generating method for generating mist or fine-bubble according to  claim 1 , wherein furthermore providing the excitation means on a rear-surface countering the surface, and exciting the surface acoustic waves on these both surfaces. 
     
     
         10 . A generating method for generating mist or fine-bubble according to  claim 9 , wherein exciting the surface acoustic waves on the both surfaces so that a mutual phase to become in phase. 
     
     
         11 . A generating method for generating mist or fine-bubble according to  claim 1 , wherein making finer bubbles by crushing the fine-bubbles generated with the surface acoustic wave by using a shock wave. 
     
     
         12 . A generating method for generating mist or fine-bubble according to  claim 1 , wherein containing the liquid in a container of a circle configuration in plan view. 
     
     
         13 . A generating method for generating mist or fine-bubble according to  claim 1 , wherein an area, the mist or fine-bubbles to be generated therein in the piezoelectric substrate, being made into positive potential to an ambience. 
     
     
         14 . A generating method for generating mist or fine-bubble according to  claim 1 , wherein an area, the mist or fine-bubbles to be generated therein in the piezoelectric substrate, being made into negative potential to an ambience. 
     
     
         15 . A generating method for generating mist or fine-bubble according to  claim 1 , wherein providing the surface with a reflective means for propagating the surface acoustic wave to one way. 
     
     
         16 . A generating method for generating mist or fine-bubble according to  claim 1 , wherein dropping surface active substances in a domain the fine-bubbles being generated. 
     
     
         17 . A generating method for generating mist or fine-bubble according to  claim 1 , wherein providing a container wrapping a portion of the piezoelectric substrate in the gas side, and filling an inside of a space formed by the container and the liquid with an arbitrary gas. 
     
     
         18 . A generating method for generating mist or fine-bubble according to  claim 1 , wherein supporting the piezoelectric substrate in a position of a definite height from the liquid level by a floating body. 
     
     
         19 . A generating method for generating mist or fine-bubble according to  claim 18 , wherein providing a circuit substrate, for controlling the excitation means, supported by the floating body. 
     
     
         20 . A generating method for generating mist or fine-bubble according to  claim 18 , wherein providing a power source, for driving the excitation means, supported by the floating body. 
     
     
         21 . A generating method for generating mist or fine-bubble according to  claim 1 , wherein generating the fine-bubbles in a liquid flowing through an inside of a tubular structure. 
     
     
         22 . A generating method for generating mist or fine-bubble according to  claim 1 , wherein providing the piezoelectric substrate and the excitation means on an internal surface of a liquid container accommodating the liquid. 
     
     
         23 . A generating method for generating mist or fine-bubble according to  claim 1 , wherein supplying an arbitrary gas into the liquid from the gas side along the surface. 
     
     
         24 . A generating method for generating mist or fine-bubble according to  claim 23 , wherein supplying the gas being performed, by giving a flow-velocity to the liquid, through a valve opened by a suction force based on a pressure drop accompanying the flow-velocity rise of the liquid, or by a kinetic energy of the liquid increasing with the flow-velocity rise. 
     
     
         25 . A generator for generating mist or fine-bubble at an interface of gas and a liquid or within the liquid, comprising:
 a piezoelectric substrate equipped with an excitation means on a surface thereof, the excitation means consisting of a plurality of electrodes to excite a surface acoustic wave; and   a substrate-holder holding the substrate, dipping in the liquid a part of the substrate so that the surface to intersect the mutual interface of the gas and the liquid, and a surface acoustic wave excited on the surface of the piezoelectric substrate existing in the upper and lower sides of the interface and propagating along the surface from the gas side to the liquid side.